The ultrasonic diagnostic apparatus transmits an ultrasonic wave to the inside of an examinee by an ultrasonic probe, receives an ultrasonic-wave reflection echo signal corresponding to acoustic impedance of each part of a tissue from the inside of the examinee to construct a tomographic image such as an ultrasonic tomographic image, and displays the tomographic image for diagnosis.
Furthermore, according to the ultrasonic diagnostic apparatus, an ultrasonic reception signal is measured while an examinee is pressed by an ultrasonic probe according to a manual or mechanical method, a displacement of each part of a living body caused by the press is determined on the basis of frame data of two ultrasonic reception signals which are different in measurement time, and an elasticity image representing hardness or softness of a living tissue is generated and displayed on the basis of the displacement data (for example, Patent Document 1).
Furthermore, elasticity information concerning a region of interest set by an operator is calculated, an elasticity image is generated on the basis of the elasticity information, and a tomographic image and an elasticity image are displayed (for example, Patent Document 2).
When a particularly detailed diagnosis is required, for example, a composite image comprising a tomographic image and an elasticity image is frozen, and a region of interest such as an affected region is observed on the basis of the frozen composite image.